Effect of C/N ratio, aeration rate and moisture content on ammonia and greenhouse gas emission during the composting

Gaseous emission (N20, CH4 and NH3) from composting can be an important source of anthropogenic greenhouse gas and air pollution. A laboratory scale orthogonal experiment was conducted to estimate the effects of C/N ratio, aeration rate and initial moisture content on gaseous emission during the composting of pig faeces from Chinese Ganqinfen system. The results showed that about 23.9% to 45.6% of total organic carbon (TOC) was lost in the form of C02 and 0.8% to 7.5% of TOC emitted as CH4. Most of the nitrogen was lost in the form of NH3, which account for 9.6% to 32.4% of initial nitrogen. N20 was also an important way of nitrogen losses and 1.5% to 7.3% of initial total nitrogen was lost as it. Statistic analysis showed that the aeration rate is the most important factor which could aifect the NH3(p = 0.0189), CH4(p = 0.0113) and N20 (p = 0.0493) emissions significantly. Higher aeration rates reduce the CH4 emission but increase the NH3 and N20 losses. C/N ratio could aifect the NH3(p = 0.0442) and CH4(p = 0.0246) emissions significantly, but not the N20. Lower C/N ratio caused higher NH3 and CH4 emissions. The initial moisture content can not influence the gaseous emission significantly. Most treatments were matured after 37 days, except a trial with high moisture content and a low C/N ratio.